assume cs:code
code segment

start:
		mov ax,cs
		mov ds,ax
		mov si,offset capital
		mov ax,0
		mov es,ax
		mov di,200h
		mov cx,offset capitalend - offset capital
		cld
		rep movsb

		mov ax,0
		mov es,ax
		mov word ptr es:[7ch*4],200h
		mov word ptr es:[7ch*4+2],0

		mov ax,4c00h
		int 21h

capital:
		push cx
		push si
		
change: 
		mov cl,[si]
		mov ch,0
		jcxz ok
		and byte ptr [si],11011111b
		inc si
		jmp short change
ok:	
		pop si
		pop cx
		iret
		
capitalend:nop

code ends

end start
